電気
In 「電気がつきません」, 「電気」 refers to the room light or electricity that should come on. It is the thing being described as not working here. It can be used before が when identifying what is on or not on. Someone would use it when reporting a problem with a light.
が
In 「電気がつきません」, 「が」 marks 「電気」 as the thing that does not come on. It identifies the subject of the situation. It commonly follows the thing whose state or action is being described. Someone would use this pattern when pointing out what is working or not working.
つきません
In 「電気がつきません」 and 「まだつきません」, 「つきません」 means that the light does not come on. The form gives a polite negative statement about the light. It is useful after a light-related subject when reporting that it has not turned on. Someone would use it when explaining that a light is still off.
スイッチ
In 「スイッチを確認しましたか」, 「スイッチ」 means the switch used to control the light. It is the object that is checked in this question. It commonly appears before を when someone checks or uses a switch. Someone would use it when asking about the control for a light or device.
を
In 「スイッチを確認しましたか」, 「を」 marks 「スイッチ」 as the object of checking. It shows what the action is directed toward. It commonly follows the thing that someone checks, uses, or changes. Someone would use this pattern when asking whether a particular object was checked.
確認
In 「確認しました」, 「確認」 names the checking of the switch or situation. Together with 「しました」, it expresses that the speaker checked it. It commonly appears before a form of する when referring to checking something. Someone would use it when verifying a setting, object, or situation.
しました
In 「確認しました」, 「しました」 says that the checking was carried out and gives the sentence a polite tone. With 「確認」, the complete expression means that the speaker checked it. It commonly follows an action noun such as 「確認」 in a polite report of a completed action. Someone would use it when telling another person that a check has already been done.
か
At the end of 「スイッチを確認しましたか」, 「か」 marks the sentence as a question. It turns the polite statement about checking into a request for information. It commonly comes at the end of a polite question. Someone would use it when asking whether another person did an action.
まだ
In 「まだつきません」, 「まだ」 means that the situation continues: the light is still not on. It emphasizes that the problem remains after the switch was checked. It commonly appears with a negative expression when something has not happened yet or is still not the case. Someone would use it when reporting that a problem remains.
電球
In 「電球が古いのかもしれません」 and 「電球を交換するまで」, 「電球」 means the light bulb. It is first suggested as the possible cause and later identified as the thing to replace. It commonly appears before が when describing its condition and before を when describing an action directed at it. Someone would use it when discussing a bulb that may need checking or replacement.
古い
In 「電球が古いのかもしれません」, 「古い」 describes the bulb as old. The description is presented as a possibility rather than a confirmed fact because of the expression that follows it. It can be placed before a possibility expression to present a possible condition. Someone would use it when suggesting that an old object may be causing a problem.
の
In 「古いのかもしれません」, 「の」 helps turn the preceding description into the matter being considered as a possibility. The whole expression means that it may be old. It is useful between a description and 「かもしれません」 in this kind of possibility statement. Someone would use this construction when making a cautious guess about a situation.
かもしれません
In 「電球が古いのかもしれません」, the whole expression means that the bulb might be old. In this construction, 「かも」 adds the possibility meaning, while 「しれません」 supplies the polite wording of the expression. It follows the matter being presented as a possibility, here 「古いの」. Someone would use it when offering a tentative explanation without stating it as certain.
今
In 「今は部屋が暗すぎます」, 「今」 means now, referring to the present situation. It sets the time for the room being too dark. It commonly appears before は when contrasting or describing the current situation. Someone would use it when explaining what is happening at this moment.
は
In 「今は部屋が暗すぎます」, 「は」 marks 「今」 as the topic or time frame. The sentence therefore describes the room's condition now. It commonly follows a time expression when focusing on what is true during that time. Someone would use it to frame a statement about the present situation.
部屋
In 「今は部屋が暗すぎます」, 「部屋」 means the room. It is the place whose lighting condition is being described. It commonly appears before が when stating a condition of the room. Someone would use it when talking about what is happening inside a room.
暗すぎます
In 「部屋が暗すぎます」, 「暗すぎます」 means that the room is too dark. The form expresses an excessive degree of darkness in polite language. It can be used after a description to say that something is excessively so. Someone would use it when the lack of light makes a place difficult to use.
小さい
In 「小さいランプ」, 「小さい」 describes the lamp as small. It comes directly before 「ランプ」 to specify which lamp is being brought. It commonly appears before a noun when describing its size. Someone would use it when distinguishing a small object from other available objects.
ランプ
In 「小さいランプ」 and 「そのランプ」, 「ランプ」 means a lamp used to provide light. It is offered as a temporary light source while the room light is not working. It commonly follows a describing word or a word such as 「その」. Someone would use it when referring to a lamp that can light a room.
持って来られます
In 「小さいランプを持って来られます」, the whole expression means that the speaker can bring a small lamp. 「持って」 links carrying the lamp with coming, and 「来られます」 expresses the ability to come in polite language. The object appears before を, followed by this expression. Someone would use it when offering to bring an item to another person or place.
あと
In 「あとで電球を交換したほうがいいです」, 「あと」 refers to a later time or afterward. With 「で」, 「あとで」 means later, when the bulb can be replaced. It commonly appears before an action to indicate when that action should happen. Someone would use it when postponing an action until later.
で
In 「あとで電球を交換したほうがいいです」, 「で」 marks 「あと」 as the time when the action is to take place. Together, 「あとで」 means later. It commonly follows a time expression to set the timing of an action. Someone would use it when saying when something should be done.
交換
In 「電球を交換したほうがいいです」 and 「電球を交換するまで」, 「交換」 means changing or replacing the bulb. Its meaning is completed through the following form of する. It commonly appears before する when describing the replacement of one item with another. Someone would use it when discussing replacing a worn-out or faulty item.
した
In 「交換したほうがいいです」, 「した」 contributes the completed-action form of 「交換」 before the advice expression. The whole phrase says that replacing the bulb would be better. It commonly appears after an action noun when that action is placed before 「ほうがいい」. Someone would use this pattern when advising that an action should be taken.
ほうがいい
In 「交換したほうがいいです」, the whole expression means that replacing the bulb is the better choice, or that the speakers should replace it. 「ほう」 presents the preferable option, 「が」 links that option, and 「いい」 means good or preferable. It follows the action being recommended. Someone would use it to give polite advice about what to do.
です
At the end of 「交換したほうがいいです」, 「です」 gives the advice a polite sentence ending. It makes the recommendation sound suitable for a polite conversation. It commonly follows 「ほうがいい」 in a polite recommendation. Someone would use it when advising another person in a courteous way.
する
In 「電球を交換するまで」, 「する」 completes 「交換する」, meaning to replace the bulb. Here it presents the replacement as the action that will mark the endpoint of the waiting period. It commonly follows an action noun to form an action expression. Someone would use it when describing an action that has not yet happened or is planned.
まで
In 「電球を交換するまで」, 「まで」 means until the bulb is replaced. It marks the replacement as the endpoint of using the temporary lamp. It commonly follows a time, event, or action that sets the limit of another action. Someone would use it when saying that something continues up to a particular event.
その
In 「そのランプを使ってください」, 「その」 means that and points to the lamp already being discussed. It comes directly before 「ランプ」 to identify the specific lamp to use. It commonly appears before a noun when referring to an item known from the conversation. Someone would use it when asking someone to use a particular previously mentioned object.
使って
In 「そのランプを使ってください」, 「使って」 means use and links the action to the polite request ending 「ください」. The object being used is marked by を before it. It commonly appears before 「ください」 when making a polite request to do something. Someone would use it when asking another person to use an item.
ください
In 「そのランプを使ってください」, 「ください」 makes the request polite, meaning please. Together with 「使って」, it asks the listener to use the lamp. It commonly follows a verb form ending in て when requesting an action. Someone would use it when giving a courteous practical instruction.